Cushion for sheet-metal presses



Aug. 12, 1930. F, J, RgDE 1,772,914 l CUSHION FOR SHEET METAL PRESSES Original Filed Many 5. 1927 2 Sheets-Sheet l Aug. l2, 193G, F. J.'RoDE i 1,772,914

CUSHION FOR SHEET METAL PRESSES Original Filed May 5. 1927 2 Sheets-Sheet 2 Watented Aug. {12;1939

'UNITED ls'rarlts PATENT. oFFlcE,

FREDBIGH il'. RODE, vOE" CHICAGO, ILLINOIS, ASSIGNOB TO MABQUETTE'TOOL & HIANU- FACTUEING CO., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS I CUSHION' FOB SHEET-METAL PRESSES Substitute for application Serial No. 188,970, led Hay 5, 1927. 'llriia application led August 205192128.

- Serial No. 800,752. v

VThis is a substitute application for application Serial Number 188,970, filed May 5, 1927. This invention relates to improvements in cushions, particularly adapted though not necessarily limited in its use, with sheet metal presses of the type generally known as double action presses, yin which the metal is shaped by/means of a blank or work holding element' that cc-operate's with a reciprocable lo die member, the blank or work holding member being resisted in its movement in one direction by the cushion. After the work has been shaped over the die, another pair of cooperating dies are brought into operation to le further shape the work,lone of the dies of the last recited co-operating pair being also resisted in its movement by the cushionrthe latter die, however, being maintained against movement until after the completion of the 2o operation of the shaping of the die by the lirst air of co-operating dies, and one of the objects of the invention is to provide an improved cushion embodying a fluid (such as air or the like) pressure resisting element for 25 one ofthe dies and an hydraulic resistance gressure'creating means for the otherof the les. e A further object isto provide improved means whereby one of the-elements 'oi the 3@ cushion will be locked againsta yieldin re1- V sistance'action while the other portiono the cushionV is active during the first step in the formation of the article, and improved means for automatically rendering the inactive cushion element active, from'a movable part ofthe press and ata predetermined time linthe cycle of operation of the press.`

To the attainmentof these ends and the ac features of novelty in substantially thecon struction, combination ,and arrangement of the several parts, hereinafter more fully described and claimed and shown in the accompanyinar drawings illustrating this invention, and in which f Figure 1 is a view in front elevation of a double acting press having a cushion embody- 5o ing the principles of thisinvention applied provided witha valve seat 25, with whic a thereto, parts being in elevation, parts being broken away and parts in section.

Figure 2 is an enlarged detail sectional view of a portion of the cushion, `showin the cooperating dies for forming the meta and at the end of the first shaping operation.

Figure 3 is a view similar to Figure 2, showing the position of the parts at the end of' the second operation.

Referring more particularly tothe drawings the numeral designates generall a sheet metal press having a bed or bolster p ate 11 mounted thereupon, uprights 12, and a reciprocable ram 13 carrying a die 14. The\' ram is connected by means of links 15 with 'a 85 crank shaft 16, which is operated in any suitable manner from any 'suitable source (not shown). A

A second crank shaft 16 is journaledupon the uprights 12 and a link 17 connects a die 18 with thecrank shaft 16. The die 18 is adapted to be reciprocated within the die 14.

All of the above referred to parts are of the ordinary and well known construction of double acting presses.

Arranged below the bed plate 11 of the machine is acylinder 19 which may be supported in any suitable manner, preferably by means ofA hangers 20 which enga e lugs or projections 21 connected to the cy inder and also a suitable stationary part of the press.

The cylinder 19 mayl be vof any desired size 'and reciprocable therein is `a piston 22. .The

cylinder vis provided with an opening 23, preferably adj acent the base thereof and below the piston 22, A valve casingf24 is supported adjacent the opening 23'and has, c ommunication therewith. The`valve casin is valve 26 Aco-operates, and thls valve 26 is .held against its seat by means of a spring 27,

the tension of which is adapted to be varied by means of an adjusting device 28 soas to vary the stress of the spring 27, against which 1 the valve 26 must be unseated by the pressure of the liquid 29 in the cylinder 19 in orderto permit the piston 22 to descend.

The valve casing is provided with ports or passages 30, any number of which may be provided, and a supplemental valve 31 coyau operates with the ports 30 to close them. This supplemental valve 3l opens in a direction opposed to the direction of opening movement of the valve 26 and is held against its seat by means of springs 32. The supplemental valve 31 is provided with an opening 33 in alinement with the opening controlled by the valve 26.

When the pressure is exerted by the piston 22 to expel the liquid from the cylinder 19, the valve 31 will be seated and the Valve 26 unseated when the stress of the spring 27 is overcome. Y

Likewise, when the liquid flows back into the cylinder 19' the valve 26 will be closed and the valve 31 will be opened against the stress of the springs 32 by the pressure of the liquid against the valve 31 through the ports 30.

Connected with the valve casing 2.4 is a pipe or conduit 34 which leads to a tank35, a T-head coupling 36'being preferably provided on the pipe 34 within the tank or container 35 so that liquid discharged back into the container will be directed towards the side of the container and will not splash up in the tank.

A check valve 37 is provided in the pipe 34 which prevents liquid from flowing from the container 35 through the pipe 34 and into the cylinder 19, but will open to permit the liquid to' How from the cylinder 19 into` the container 3,5.

A by-pass 38 is provided in the pipe 34 around the valve 37. Wit-hin this by-pass is arranged a valve v39 having a stem 40, which is connected by means of a link 41 to a movable part of the press 42, preferably a part of the crank shaft 16. A resilient connection 43 is provided in the link 41 so as to prevent injury to the parts.

Connected with the piston 22 is a piston `rod 44 which passes through a suitable stuiiing box 45 in the end of the cylinder 19. The piston rod passes loosely through the bedor bolster plate 11 and has connected with it a die 46.

Interposed between the bed or bolster plate 11 and the cylinder 19 is another cylinder 47 which is closed at its top as at 48, and theend 49 of the cylinder 19 telescopes into the cylinder 47 and constitutes a piston for the last recited cylinder.

A packing 50 maybe provided on the pis ton end 49 of the cylinder 19, if desired.

The cylinder 19 is provided with a vent 4 opening 51 between the piston 22 and the end 49 thereof, so as 'not to interfere with -the operation of the piston 22.

The other end 52 of the c linder 47 is sha ed to formapressure pa or pin plate which in its `normal position is adapted to assume a position in close bed or bolster plate. 11. Pins 53 pass loosely through the bed or proximity to the bolster plate 11 and rest upon the end 52 of the cylinder 47. These pins 53 support a die 54 which encompasses the die 46, and the pins are of such a. length that in the normal elevated positions of the dies 46 and 54, the upper surfaces of these dies will be Substantially iush so as to support the work 55.

The die 46 operates within a guide or member 56 and the end 52 of the cylinder 47-ma be provided with packing 57 through whic 1 the piston rod44 passes.

The die 54 co-operates with the die 14 on l `the ram of the press and the die 46 co-operates with the die 18.

Fluid, such as air, is supplied to the cylinder 47 by means of a pipe 57 whichl communi- Cates with a port or assage 58 that leads through the end 49 o the`cylinder 19 and discharges into the cylinder 47.

The fluid is supplied from any suitable source such as a' tank or container 59, from which a pipe 60 leads that is connected with the pipe'57. A control valve 61 may be provided in the .pipe 60 and a safety valve 62 may also be provided.

An automatic pressure control valve 63 may be provided in the pipe line.

A valve 64 may be provided in the pipe 57 and is adapted to be opened so as to exhaust the'fluid from the cylinder 47 and thereby allow the cylinder 47 to drop with respect to the cylinder 19 so as to lower the pad or pin plate 52 as well as the pins 53 and die 54.-

The operation of this improved cushion is as follows.

Assuming the parts to be in the position Vshown in Figure 1, with the cylinder 47 iilled with fluid (air) under a predetermined pressure and the piston 22 elevated to the limit of its upward movement by means of the liquid 29 and the valve 26 to be set at a predetermined resistance pressure, and the liquid in the tank or container 35 is 'under a predetermined pressure, the upper surfaces of the dies 46 and 54 will be substantially flush so as to support the work 55.

The valve 39 will be closed and the valve 64 will be closed while the valve 61 willbe open.

When the ram 13 descends the die 14 will contact with the work 55 and will cofoperate with the die 54 to clamp the work therebetween. The die 46 will be locked against a descending movement until the pressure of the spring 27 is overcome. This spring pressure, however, is set so that the work may be formed over the die 46 by the co-operation of the dies 14 and 54, and the die 46 will be maintained in a locked position until the parts have-assumed the position shown in Figure 2. While assuming this position,.the die 54 wi1l be lowered against the stress of the fluid pressure, in the cylinder 47, the resistance pressure being such as to cause the die 54 to cooperate With the die 14 with sufficient strength to grip the work therebetween and hold it' in the cycleof operation of the press, the work -whlle 1t is being shaped over the die 46.

Just at the completion of the forming of the work 55 by the dies 14 and 15 over the die 46, the valve 39 will be opened by the link 41 so that when the dielSdescends, at this point will be gripped by the dies 54 and 14.and the vdie 18 will move into engagement with the work 55' within the die 54 and shape the work over the dL 46 as shown in Figure 3. The

die 46 in its lowering movement will be re` sisted by the pressure of the liquid 29 upon the piston 22 and the resistance pressure of the valve 26. When the pressure on the liquid 29 exceeds the pressure on the valve 26 the der 19.

liquid will be discharged into the pipe 34 and back into the 'tank 35 throu h the pipe 34.

The center dies or punc es 18 and 46 descend while the blank holder` 54 which operor unlocked to permit of such function .of the dies 46 and 18. This unlocking may be accomplished in any suitable manner, preferably by means of a lever 46a pivotally mounted at one end as at 46".` The lever is disposed adjacent the valve 26 and engages an antifriction roller 46c on the element 46' against which latter the spring 27 rests. Connected with the lever is one end o a link 46, the other end bein connected as at 46t to one arm of a bell cran lever 46g. The other end of the-bell crank lever is connected `lby a link 46h preferabl to the rod 41. As the 4rod 41 is lowered, t e bell crank lever 46g will be rocked to rock the 4lever 46 and open the valve 26 against the stress of the s ring 27,

\ permitting the liquid in theccylin er 19 to escape, thereby releasing or unlocking the die 46. H

y At the completion of the operation of thev forming of the work the blank will rise'under the pressure of the Huid inthe cylinder 47 and the center punch or die 46 will be retamed in its lowered position until after the ram starts to ascend. This is due to the fact that the valve 39 will then be opened at that pointin the cycle of operationof the press to permit the liquid from the tank 35 to 'be deliveredback into the cylinder 19 under .the

v piston 22 tor elevate the same.

' ',Whilefthe. preferred form of the invention has hmeenfherein shown and described; it' is to be understood that various changes may llbe made in the details of construction and in the combination and arrangement of the several parts, within the scope of =the claims,

without departing from the spirit of this invention. Y

What is claimed as new is `1. In a double acting sheet metal press two dies, each of said dies embodying co-operating work gripping and shaping members, a uid pressure cushion for yieldingly resisting themovement of one of the members of one of said pairs in one direction, an hydraulic cushion :for yieldingly resisting the fmovement of one of the members of the other pair in one direction, means operable from a movable part of the press for rendering one of said cushions inactive and active for yieldin resistance pressure and for auto- 'matica y H,shifting the yielding resistance pressure from one to the other of the cushions, and means for relieving at will the iiuid ressure cushion of the iuid therein.

- 2. n a sheet metal press, a pressure pad,

an hydrauliccushion for yieldingly resisting the movement o said pad in one direction, variable resistance pressure creating means for controlling the pressure in the cushion,

and mechanical means for rendering the variable resistance .pressure creating means inactive. 4

3. In a sheet metal press. a pressure pad, an hydraulic cushion for yieldingly resisting the movement of said pad in one direction,

variable resistance pressure creating means for controlling the pressure in the cushion, and means for automatically rendering the variable resistance pressure creating means inactive at a predetermined time in of operation of the press.

4. In a sheet metal press, a pressure pad, an hydraulic cushion for yieldingly resisting the movement of said pad in one direction, variable resistance pressure creating the cycle...

means for controlling the pressure in the',

cushion, and means responsive to the operajtion of a movable-part of the press for 'rendering the variable resistance pressure creating means inactive below the pressure for which it is set.

5. In 'a sheet metal press, a cushion embodying a cylinder and piston, means for ,supplymgluid to the cylinder, a variable reressure creating valve :for consistalce u u trolling t e outlet of the uid from the cylinder, and positively actuated means rendered active at a predetermined time in the cycle of operation for rendering the said valve 1n- 'active below the pressure aft which the valve is' o rable to rmit the escape of a portion of uid from t e cylinder. l

6. In a sheet metal press, a cushion embodying. acylinder and' piston, 'means for Supplies controlling the outlet ofthe cylinder, vai-1able resistance pressure creating means operating upon the valve, and positive means also iluidl to the cylinder, a valve 'for operable upon the valve tounseat the same against the stress of the last said means.

7. In a sheet metal press, a cushion embodying a cylinder and piston, means for supplying fluid to the cylinder, a valve vfor controlling the outlet of the cylinder, variable resistance pressure creating means operating upon the valve, and positive means responsive in its operation to the movement of a movable part of the press for unseating said valve against the stress ofA lsaid resistance pressure creating means and' below the resistance pressure at which the valve is set.

8. In a sheet metal press, a cushion embodying a cylinder and piston, means for supplying fluid to the cylinder, a valve for controlling the outlet of the cylinder, variable resistance pressure creating means operating upon the valve, positive means also operable upon the valve to unseat the same against the stress of the last said means, and means for varying at will the stress of -sa-id resistance pressure creating means.

9. In a sheet metal press, a cushion embodying a cylinder and piston, means for supplying fluid to the cylinder, a Valve for controlling the outlet of the cylinder, variable resistance pressure creating means operating upon the valve, positive mea-ns responsive in its operation to the movement of a movable part of the press for also unseating said valve against the stress of said resistance pressure creating means, and means controllable at will for varying the stress of the said resistance pressure creating means.

l0. In a sheet metal press, a pressure pad, a luid cushion for yieldingly resisting the movement of said pad in one direction, variable resistance pressure creating means for controlling the pressure in the cushion, and means for rendering the variable resistance creating means inactive below the pressure for which it is set. Y

11. In a sheet metal press, a pressure pad, a fluid pressure cushion for yieldingly resisting the movement of the pad in one direction, variable resistance pressure creating means for controlling th pressure ci the cushion, the said means embodying a valve set to be unseated at a predetermined pressure, and

positive means for also unseating said valve.

for controlling the pressure of the cushion, said means embodying a spring pressed valve adapted tobe unseated at a predetermined pressure of the fluid, and means independent of said iuid pressure for unseating the valve against the stress of said spring.

14. In a sheet metal press, a pressure pad, a fluid pressure cushion for yieldingly resisting the movement of the pad'in one direction, a variable resistance pressure creating means for controlling the pressure of the cushion, said means embodying a spring pressed valve adapted to be unseated lat a predetermined pressure of the fluid, mechanical means rendered active at a predetermined time in the 'cycle of operation of the press for unseating the valve against the stress of said spring, and means for varying at will the stress of the spring.

In testimony whereof I have signed my name to this specification, on this 17th day7 of August, A. D. 1928.

FREDRICH J. RODE.

12. In a sheet metal press, a pressure pad,

arfluid pressure cushion for yieldingly resisting the movement of the pad in one direction,

variable resistance pressure creating means for controlling the pressure of the cushion, the said means embodying a valve set to be unseated at a predetermined pressure, andl means other than the Huid pressure in the cushion for unseating said valve regardless of the pressure in the cushion.

13. In a sheet metal press, a pressure pad, a fluid pressure cushion for yieldingly resisting the movement of the pad in one direction,

' a variable resistance pressure creating means 

